Base Transceiver Station with Distortion Compensation

1. Base transceiver station for a radio communication system, the base transceiver station having a transmitter unit, a receiver unit independent of said transmitter unit, and a transmit path between the transmitter unit and an antenna and a receive path between the receiver unit and said antenna, wherein the receiver unit determines output data from received signals and the transmitter unit converts input data into transmitted signals and pre-distorts the transmitted signals using at least one compensation value, and wherein the base transceiver station further comprises: a branching unit for transferring at least a portion of a transmitted signal from the transmit path to the receiver unit; and a processing unit independent of said transmitter which is adapted to receive a representation of the input data to said transmitter unit and the output data from said receiver unit; the processing unit being further adapted to compare the input data to the output data, to determine a first compensation value for the pre-distortion according to the comparison, and to update the compensation value of the transmitter unit with the first compensation value; wherein said receive path is adapted to transfer the output of the branching unit to the receiver unit, and wherein the processing unit compares the input data to the output data and determines the first compensation value according to the comparison.

2. Base transceiver station according to claim 1 , wherein the branching unit comprises a converter for converting the frequency of the transferred signal to the input range of the receiver unit.

3. Base transceiver station according to claim 2 , wherein the converter comprises a mixer and an oscillator and the mixer mixes a signal generated by the oscillator and the transferred signals.

4. Base transceiver station according to claim 2 , wherein the branching unit comprises an element for delaying the transferred signal.

5. Base transceiver station according to claim 2 , wherein the branching unit comprises a connection between the transmit path and a receive path connecting an antenna and the receiver unit.

6. Base transceiver station according to claim 2 , wherein the transmit path and a receive path connecting an antenna and the receiver unit have a common section and the branching unit feeds the transferred signal into the common section.

7. Base transceiver station according to claim 1 , wherein the branching unit comprises an element for delaying the transferred signal.

8. Base transceiver station according to claim 1 , wherein the branching unit comprises a connection between the transmit path and a receiver path connecting an antenna and the receiver unit.

9. Base transceiver station according to claim 1 , wherein the transmit path and a receive path connecting an antenna and the receiver unit have a common section and the branching unit feeds the transferred signal into the common section.

10. Base transceiver station according to claim 1 , wherein the branching unit is connected to the transmit path near an antenna reference point.

11. Base transceiver station according to claim 1 , wherein the branching unit is connected selectively to the transmit path and a receive path with a device selected from a group comprising a coupler and a switch.

12. Base transceiver station according to claim 1 , wherein a combining and distribution unit comprises the branching unit.

13. Base transceiver station according to claim 1 , wherein the content of a transmitted signal corresponds to a complex signal vector.

14. Base transceiver station according to claim 13 , wherein the transmitted signals are EDGE signals or UMTS signals.

15. Base transceiver station according to claim 1 , wherein the processing unit determines further compensation values for different frequencies of transmitted signals.

16. Method for the correction of signal distortions in a base transceiver station provided with a transmitter unit and a receiver unit independent of said transmitter unit, wherein transmitted signals are sent from the transmitter unit over a transmit path to an antenna, the method comprising the steps of: determining first signals for transmission from input data and sending them into the transmit path; branching off at least a portion of the first transmitted signals from the transmit path; transferring the branched off signals to the receiver unit; calculating output data from the signals transferred to the receiver unit; comparing the input data and the output data in a processing unit independent of said transmitter unit; determining at least one first compensation value according to the comparison; and adjusting further transmitted signals according to the first compensation value.

17. Method according to claim 16 , wherein the first transmitted signals are determined using a preceding compensation value and the preceding compensation value is adjusted by the first compensation value.

18. Method according to claim 17 , wherein the frequency of the transferred signal is converted to the input range of the receiver unit.

19. Method according to claim 17 , wherein the signal is transferred to the receiver unit (RU) with a delay.

20. Method according to claim 17 , wherein the content of a transmitted signal corresponds to a complex signal vector.

21. Method according to claim 16 , wherein the frequency of the transferred signal is converted to the input range of the receiver unit.

22. Method according to claim 16 , wherein the signal is transferred to the receiver unit with a delay.

23. Method according to claim 16 , wherein the content of a transmitted signal corresponds to a complex signal vector.

24. Method according to claim 23 , wherein the transmitted signals are EDGE signals or UMTS signals, selectively.

25. Method according to claim 16 , wherein further compensation values are determined for different frequencies of transmitted signals.

26. Method according to claim 16 , wherein the method is performed during a low traffic period.